It is known to provide at a base station of a cellular wireless communications system, such as a system carrying AMPS (Advanced Mobile Phone System) signals, two spaced antennas the received signals from which are combined with respective weights to provide a combined received signal which has reduced susceptibility to adverse conditions such as signal fading and co-channel interference. The weights must be adaptively adjusted in a rapid manner to provide a short training time for initial set-up and to track interference changes in a fast fading environment. A reliable reference signal is required to identify the desired signal and reduce the probability of the desired signal being nulled during fading or error conditions, and a fast recovery is required from any situation in which the desired signal is nulled as a result of being erroneously treated as interference.
An object of this invention is to provide an improved method of and apparatus for diversity combining received signals in a communications system.